Colorado regulators on Friday recalled recreational marijuana grown and sold by two prominent Boulder County cannabis businesses — The Farm in Boulder and Headquarters Cannabis Co., which has shops in Lyons and Boulder — over concerns the plants were grown with unapproved pesticides.

The recalls, called health advisories by the state, are the eighth and ninth holds announced by the Colorado Marijuana Enforcement Division since its first on Feb. 19.

The advisories note that 16 batches of The Farm’s marijuana tested positive for avermectin and 36 batches of Headquarters’ cannabis tested positive for spiromesifen.

The Guardian news shocked legal cannabis growers attempting to adhere to ever-changing state guidelines as well as the agencies regulating the marijuana cultivators. In late-January, the Colorado Department of Agriculture pulled Guardian from its list of allowable pesticides for use on cannabis, and the Oregon Department of Agriculture did the same in early February.

“From the grower’s perspective, it was a popular product and everybody was talking about it and praising it because it was this natural product that was working really well,” said Alison Ledden, marketing director for The Farm. “And lo and behold, (Guardian) had this insecticide inside it that nobody knew about it.”

Ledden said The Farm’s cultivation team, which only sprays pesticides during a plant’s vegetative state, stopped using Guardian after stories first reported the presence of abamectin. The Boulder shop tested its marijuana for pesticide residues after the initial report, she said, and the tests came back negative. The Farm has all of its recalled product in custody, and a company statement said “it will be properly destroyed.” (Read the full company statement on the next page of this story.)

More marijuana grown with unapproved pesticides has been recalled in Colorado. (Associated Press file)

Ledden and her colleagues are now curious how the state, which allowed Guardian on cannabis as recently as January, will handle recalls of businesses that were lawfully using the now-tainted product.

“It was on the state’s approved list,” said Ledden. “The fact of the matter is, Guardian lied to everybody.”

A representative with the Colorado Department of Agriculture on Friday told The Cannabist that if “this case does in fact involve Guardian, and its pesticide Abamectin is the only ingredient found, then we can take that into consideration in determining any potential violations of the (Pesticide Applicators Act). But it does not change the MED’s responsibility to protect the public from illegal pesticide residues under the Executive Order.”

Headquarters Cannabis Co.’s ownership did not respond to e-mails and phone calls on Friday.

Consumers who have any of the recalled retail pot products from The Farm or Headquarters Cannabis Co. should return it to the place of purchase to ensure it is disposed of properly, the state said.

It is unclear how large the recalls are or how many actual products or plants are affected. Product labels will contain the businesses’ recreational license numbers — 403R-00275 for The Farm’s products and 403R-00445 for Headquarters’ products.